Cyber blowing F1 fuse on power-up

I have a Cyber that instantly blows fuse F1 when the unit is switched on.

Tried a different power factor cap - same thing. Swapped the PSU board with a working unit and the problem followed the PSU board. Also tried powering-up without a lamp - no difference.

So am assuming the problem lies somewhere on the PSU board.

Any suggestions as to likely faulty components?

Thanks,

Scotty.
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    In retrospect, SC5 and SC6 could also cause the same thing to happen . . . Do you have a decent meter? Read across these components, and see if any of them show a short . . . Since you say the problem follows the PSU board, then that rules out the transformer, and anything on the logic card . . . and the only thing that feeds from the transformer that does not have it's own fuse is the 24V supply . . . if any other was bad, you would be failing F2 or F3, unless one is grossly oversized . . .

    If you can remove lead 4 or 5 from the transformer connector, that will isolate the 28V AC/24V DC supply, and if the unit will come up and F1 will hold, then that confirms that the location of the problem. From there, it's a matter of getting out the schematics and working your way through the circuit, but the only two solid state devices that are across the 28V line are the ones I mentioned, and then there is C7 on the output side, which could also fail . . .

    Page 6 of the Cyber power board schematic is your friend . . . www.highend.com/pub/products/automated_luminaires/CyberLightTurbo/Cyber_PSB.pdf

    - Tim
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  • 0
    In retrospect, SC5 and SC6 could also cause the same thing to happen . . . Do you have a decent meter? Read across these components, and see if any of them show a short . . . Since you say the problem follows the PSU board, then that rules out the transformer, and anything on the logic card . . . and the only thing that feeds from the transformer that does not have it's own fuse is the 24V supply . . . if any other was bad, you would be failing F2 or F3, unless one is grossly oversized . . .

    If you can remove lead 4 or 5 from the transformer connector, that will isolate the 28V AC/24V DC supply, and if the unit will come up and F1 will hold, then that confirms that the location of the problem. From there, it's a matter of getting out the schematics and working your way through the circuit, but the only two solid state devices that are across the 28V line are the ones I mentioned, and then there is C7 on the output side, which could also fail . . .

    Page 6 of the Cyber power board schematic is your friend . . . www.highend.com/pub/products/automated_luminaires/CyberLightTurbo/Cyber_PSB.pdf

    - Tim
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